In The News

Fixing Fukushima

On the afternoon of March 11, 2011, a 9.0-magnitude earthquake occurred off Japan’s northeast coast. About 50 minutes after the quake, a 45-foot-high tsunami slammed into the Japanese coastline. More than 18,000 people were killed, 300,000 were evacuated, and entire communities were destroyed.

And as if two natural disasters in less than an hour weren’t devastating enough, the quake initiated the meltdown of three reactors at the Fukushima Daiichi nuclear power plant. A plan for locating and removing the melted fuel is just now coming to fruition—thanks to a technology developed by Los Alamos scientists.

The quake initiated Fukushima’s automatic reactor shutdown. It also cut off the reactor complex from the electric power grid. However, the tsunami that followed overwhelmed the 30-foot-high seawall that Japanese experts believed would protect Fukushima, swamped the lower floors of the reactor buildings with 15 feet of water, and permanently knocked out the reactors’ emergency electric generators—and with them, their cooling-water circulation pumps. The reactors’ cores containing hot nuclear fuel lost critical cooling and some (perhaps all) of the fuel became so hot it melted. Life-threatening radiation was released.

Now, more than five years later, radiation levels inside the buildings that contained the melted fuel are still lethal. The deadly fuel must be removed, but key questions still need definitive answers. Before the process of fuel removal can begin, the exact status of the fuel must be known. How much has melted? Where is it? The Japanese government, nuclear engineers, and plant operators will not have the answers until they can see inside the reactors. Yet without technology that allows them to proceed safely, the Japanese cannot begin the process.

Muon vision

That’s where Los Alamos National Laboratory comes in. Los Alamos scientists have created a new type of penetrating “vision” that can detect nuclear materials, such as uranium and plutonium, hidden inside very thick layers of concrete and steel. This so-called muon vision (see “What is Muon Vision?” page 39, attached) uses cosmic ray muons, which are always present and which, unlike x-rays, are harmless to humans. Muon vision has already been commercialized. Los Alamos and California-based Decision Sciences International Corporation (DSIC) have worked together to create a unique muon vision system to scan cargo containers and trucks at ports and border crossings for concealed uranium and plutonium (see “Muon Vision for U.S. National Security,” page 46, attached). Now Los Alamos and DSIC are partnering with Tokyo-based Toshiba Power Systems Company to use muon vision to safely investigate the Fukushima reactors. If the technology works on this large-scale application—and muon vision inventor Chris Morris, a physicist at the Los Alamos Neutron Science Center, believes it will—muon vision could reduce the time it takes the Japanese to clean up the site by 10 years.